Chimney cap



June 8, 1954 c. w. ADELT CHIMNEY CAP Filed Feb. 15, 1952 h\ VENTOR ATTOhNEYS.

Patented June 8, 1954 UNITED STATES ATENT OFFICE CHIMNEY CAP Carl W. Adelt, Mays Landing, N. J. Application February 15, 1952, Serial No. 271,697

1 Claim. 1

This invention relates to chimney structure, and more particularly to a novel chimney top or cap which increases the height and reduces the cross sectional area of a chimney flue at the top of the chimney.

It is among the objects of the invention to provide an improved chimney cap which can be easily and securely mounted on the top of a chimney to provide a fine extension of reduced diameter and cause a more rapid expulsion of combustion gases from the chimney; which retains heat in the chimney to improve draft, particularly in the case of thermostatically controlled furnaces having on and 01f periods of operation; which minimizes the 'eiTect of wind on the draft and materially reduces the condensation of moisture in the chimney, which prevents birds from nesting in the chimney; which is a substantially unitary structure having no moving parts; and which is simple and durable in construction, economical to manufacture, and

neat and attractive in appearance.

Other objects and advantages will become apparent from a consideration of the following description and the appended claim in conjunction with the accompanying drawing wherein:

Figure 1 is a perspective view of a chimney cap illustrative of the invention;

Figure 2 is a longitudinal, medial cross sec-,

tional view of the chimney cap illustrated in Figure 1;

Figure 3 is a transverse cross sectional view on the line 33 of Figure 2;

Figure 4 is a cross sectional view similar to Figure 2 showing a somewhat modified form of chimney cap;

Figure 5 is a cross sectional view similar to Figures 2 and 4, showing a still further modified form of chimney cap; and

Figure 6 is a cross sectional view similar to Figures 2 and 4 showing an additional modification of the chimney cap.

With continued reference to the drawing, the illustrated chimney cap comprises a base plate I of square or rectangular shape, preferably formed of a suitable sheet material, and adapted to be mounted on the top of a chimney II and secured to the chimney by suitable means, such as a layer of mortar or plaster I2 disposed on the top of the chimney and extending over the edges of the plate.

The plate It! is provided with a centrally disposed aperture I3 of circular shape and a sleeve or tube M, of substantially cylindrical shape in the form of the invention shown in Figures 1, 2

2 and 3, is secured at one end in the aperture I3 in the base plate I0 and extends from one side of the base plate with its center line substantially perpendicular to the plane of the edges of the base plate.

A shell I5 of truncated conical shape spacedly encloses the pipe I '4 and has its smaller end closely surrounding and secured to the end of the pipe 14 remote from the base plate I0. At its other end the shell i5 is secured to the base plate circumspatially of the end of the pipe 1 3 secured in the base plate aperture I3. I'he annular portion I5 of the base plate between the aperture I3 and the end of the shell I5 secured to the base plate is dished or inclined in a direction away from the end of the shell I5 secured to the base plate and away from the end of the pipe I4 se cured to the smaller end of the shell, as is particularly illustrated in Figure 2, providing an annular ridge I? at the end of the pipe I4 secured to the base plate which ridge extends down wardly into the top end of the chimney flue pipe I8. A porous layer I9 of insulating material covers the inner surface of the shell I5 and a layer 20, of heat retentive material, such as sand or metal shavings covers the inner surface of the dished portion IB of the base plate I0, the layers of material being disposed within the annular chamber 2! between the pipe I4, the shell I5 and the portion of the base and the shell.

As illustrated in Figure 3, the layer ill of insulating material may comprise a sheet 22 of corrugated asbestos paper disposed against the inner side of the shell I5 and a sheet 23 of plain asbestos paper disposed against the inner surface of the corrugated sheet 22. The layer 20 of heat retentive material may have a similarly constructed layer of insulating material at the side thereof remote from the base plate.

The insulating material, as illustrated in Figures 2 and 3, may be omitted from the inner side of the shell, if desired, but in all cases a body of heat retaining material, such as sand or metal shavings, will be provided on the inner surface of the annular portion of the base plate between I the sleeve and the shell to maintain the flue temperature during off periods of the associated furnace, and this body of heat retaining or absorbing material may be covered by a layer of heat insulative material, if desired.

When the chimney cap, as above described, is mounted in operative position on the top of a chimney, as illustrated in Figure 2, the sloping plate between the pipe annular portion l6 of the base plate causes any moisture condensing on the under surface of the base plate to drain to the lower end of the pipe M where it is evaporated by the hot exhaust gases passing through this pipe and carried out of the chimney. The insulation in the chamber 2| prevents rapid heat loss from the top of the chimney and maintains the temperature of the chimney at a value at which fog will not settle into the chimney and an efficient draft will be provided at all times and back draft eliminated.

In the modified arrangement illustrated in Figure 4, the tube 26 is also of frusto-conical shape, but having a much smaller inclination than the frusto-conical shell 27. This upwardly tapered or frusto-conical shape of the tube 26 increases the speed of the combustion gases leaving the chimney and provides a much more eifective draft in certain installations.

In the modified arrangement shown in Figure 5, the tube 28 and shell 29 are also both of frustoconical shape, but difier in shape from the tube and shell illustrated in Figure 4 in that in the form shown in Figure both the tube and shell are concavely curved longitudinally giving a somewhat bell shape to the entire chimney cap. In this last modification the annular portion iii! of the base plate 3| between the larger ends of the tube and shell is also much more steeply inclined than the corresponding annular portions of the above described modification providing a more pronounced annular ridge at the top of the chimney flue for the collection and evaporation of condensed moisture.

In all cases, the tube and shell are preferably of circular cross sectional shape and the tube, shell and base plate are preferably formed of a suitable heat and corrosion resistant sheet material, such as stainless steel, to increase the 4 durability and enhance the appearance of the device.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claim is, therefore, intended to be embraced therein.

What is claimed is:

In a chimney cap, a base plate provided with a central opening, a vertical tube having an open lower end and an open upper end, said lower end being secured in said central opening, a frustoconical shell surrounding said tube, said shell having a smaller upper end secured around an upper part of said tube and a larger lower end secured to said base plate in concentrically spaced relation to the lower end of said tube and defining a chamber surrounding the tube, the area of said base plate between the lower end of said shell and the lower end of the tube declining toward said tube so as to cause any moisture condensing on the under surface of the base plate to drain to the lower end of the tube where it is evaporated by the hot exhaust gases, and a porous layer of heat retentive material resting upon and covering said area of the base plate.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 454,492 Oster June 23, 1891 1,751,026 Blanchard Mar. 18, 1930 1,794,140 Blanchard Feb. 24, 1931 2,408,665 Lovely Oct. 1, 1946 

